Container ship having bridge mounted travel crane



Mam, 1951 L. D. SMITH EI'AL CONTAINER SHIP HAVING BRIDGE MOUNTED TRAVEL CRANE 5 Sheets-Sheet 1 Filed May 28, 1945 INVENTORS zze May 29, 1951 1.. D. SMITH EIAL CONTAINER SHIP HAVING BRIDGE MOUNTED TRAVEL CRANE Filed May 28, 1945 5 Sheets-Sheet 2 IN V EN TORS 652720 7715572 CONTAINER SHIP HAVING BRIDGE MOUNTED TRAVEL CRANE Filed May 28, 1945 May 29, 1951 1.. D. SMITH ETAL 5 Sheets-Sheet 3 May 29, 1951 L. D. SMITH ETAL 2,555,297

CONTAINER SHIP HAVING BRIDGE MOUNTED TRAVEL CRANE Filed May 28, 1945 5 Sheets-Sheet 4 i "nu 3W1 Rune May 29, 1951 D. SMITH ETAL' 2,555,297

CONTAINER SHIP HAVING BRIDGE moun'nzo TRAVEL cam:

Filed May 28, 1945 5 Sheets-Sheet 5 Patented May 29; 1951 UNITED STATES ATENT OFFICE CONTAINER SHIP HAVING BRIDGE MOUNTED TRAVEL CRANE Application May 28, 1945, Serial No. 596,124

1 Claim.

This invention relates to a container ship carrying a bridge mounted travel crane, and more particularly to a ship travel crane which within limits can hold a load suspended in a cargo hold in fixed relationship to bulkheads and the like irrespective of rolling of the ship. This invention is one of several which seeks to render practical a. seagoing container ship, and is a continuationin part of application Serial N 0. 532,240, issued as Patent No. 2,440,306, April 2-7, 1948. Also seeconcurrently filed application Serial No. 586,522, filed by Leathem D. Smith, et al., and now Patent No. 2,539,168, granted January 23, 1951, and Patents 2,440,306, 2,440,307, and 2,- 457,841.

The first general object of this invention is to provide a container ship having cargo loading means which can function safely and rapidly when the ship is in motion and slightly rolling. The problem. is particularly acute in a container ship employing applicants beam type hold, see copending application Serial No. 586,521, issued as Patent No. 2,440,307, April 27, 1948, because containers located in the lower part of the holdmust pass close to fixed beams which have sufficient clearance to pass only the short dimen-- sions of the containers. The raising of a container from the lower hold when the ship is only slightly rolling by means of a cable working from the end of a boom will result in the container swinging as the ship rolls and striking adjacent containers or beams or otherwise doing damage. However, the problem isto a lesser extent existent when it is desired to move at sea cargo around a hold or from hold to hold in conventional seagoing ships.

The second object of this invention is to providea. loading means for a container ship which is capable of accurately positioning containers on a fiat surface such as a wharf so that the containers may be stacked one on top of the other. According to existing loading and unloading practices at wharfs, stevedores are continuously moving cargo to the edge of a wharf so that the booms or cranes on the vessel can get above the cargo and lift it aboard, or conversely, if they are unloading, the cargo is dropped at the edge of a wharf and stevedores are continuously moving it back so additional cargo can be unloaded. This practice makes the loading or unloading of ships dependent entirely upon the availability of stevedores, a human factor so subject to unpredictable and uncontrollable factors that ships spend an unwarranted amount of time in port duringwhich time they earn no money.

More specific objects will appear as the construction is described. Anernbodiment of the invention is disclosed in the drawings comprising live sheets wherein:

Figure 1 is a side view partially in section and partially in side elevation of a container ship carrying a bridge mounted travel crane;

Figures 2 and 3 are schematic views of a cross section and a side'elevation of a ship illustrating the importance of holding a container from a point as close to the longitudinal axis ofthe ship as possible;

Figure 4 is across section of applicants container ship showing a bridge mounted travel crane holding a container between two longitudinally positioned beams when the ship's hold is at a 15 degree angle;

Figure 5 is a cross section of a modified form ofapplicants bridge mounted travel crane which may be used where there is only one deck of cross beams and theyare positioned transversely of the ship;

Figure 6 is a side view of applicants bridge mounted travel crane showing the auxiliary bridge partly extended;

Figure 7 is an end elevation of applicants travel crane;

Figure 8 is a plan view of applicants" travel crane; and

Figure 9 is an enlargement of the lower end of the lift beam on applicants travel crane and illustrates the holding means.

Bridge. mounted travel cranes supported on the ship sheer have not been used on lake or seagoing vessels, firstly because their principal advantage, namely the ability to get directly above the object to be lifted; does not exist because hatch decks and between decks, broken by comparatively small hatches, cover much cargo space in a ship. hold. Secondly, the swinging boom is considerably faster than the bridge mounted travel' crane where accuracy of positioning the load is not wanted and where the lifting job is along a curved path from the inside of a ship hold over the side and back down to the wharf.

A few fundamentals on this matter are of much importance in designing a lifting device for a container ship designed to permit the rearrangement of containers during travel at sea. Referring to Figure 2, a cross sectional view of the hull of ship 10 is shown with a container II in the bottom of the hold and a container l2 in the upper part of the hold. Above these two containers is a point l3 which identifies the position of a pulley on a boom or on any other kind of a crane from which depends a cable or rope to lift cargo. The point I3 is positioned above a hatch deck l4 by a distance just sufficient to permit a container such as 12 to be drawn up beneath l3 and by moving l3 horizontally to clear either the side of the ship or to clear hatch coamings between hatches. Assuming that the ship rolls 15 degrees in the direction of the arrow l5, the container l2 would assume the position indicated by the dotted outline I6 while the container l I would occupy the position ll. Similarly, referring to Figure 3, if the hull was pitching about the center [8 by as much as 15 degrees, the containers H and I2 would occupy the positions l9 and 20 respectively. Generally speaking, therefore, the deeper a cargo item is in the hold, the more it will be displaced laterallythat is, the more it will swing-for a given degree of rolling or pitching of the ship.

Returning to Figure 2, the point 2| is, when measured from the hatch deck M, of the ship, twice as high as the point [3. If a container II was suspended from the point 2|, for the same 15 degree roll, it would swing into dotted position 22. Compare this position with position 23 in Figure 3. The general statement may therefore be made that the higher the lifting point is above the hatch deck, the greater the swing of an item of cargo for a given degree of roll and a given position in the hold of the ship.

When a ship is not rolling it is immaterial whether the lifting means is at point I3 or point 21 of Figures 2 and 3. An ordinary boom type crane is therefore commonly used because while the boom raises and lowers to move the load to selected horizontal positions, no evil swinging of the load due to movements of the ship affect the boom because the ship is still in a harbor.

The conclusion of applicants analysis of the needs for shifting cargo at sea or unloading cargo in open roadsteads at sea is that a constant level for the pulley over which the lifting cable is drawn is desirable and secondly, that the closer this level is to the hatch deck, the less lateral movement of a unit of cargo for a given degree of rocking of the vessel.

Applicants have therefore utilized a bridge mounted travel crane which, referring to Figure 1, comprises a bridge 25, vertical supports 26 and 21, supporting wheels 28 and 23 and a travel crane 3U. Rails 3| and 32 positioned on the port and starboard stringers make it possible for the travel crane to position itself over any hatch. The height of the point 33 at which a supporting cable swings clear of the travel crane 30 is such that one of applicants standard containers can be passed endwise between the supports 26 and 21.

Figures 4 and are diagrammatic illustrations of applicants presentation of the serious obstacle presented to moving cargo when there is a slight roll or pitch on the ship and applicants solution thereof. a tank top 36, decks of longitudinally extending beams 31, and 38 identifies a bridge mounted travel crane having a traveling unit 39. Applicants containers when loaded may weigh as much as eight or nine tons. At the moment when such a container is lifted off the tank top 36 when the vessel is at sea, there will be some sort of a roll to the ship, from one to five degrees. This is calm weather. Assuming a roll of five degrees and a cable pulley 40 to 50 feet above the tank top, the eight or nine ton container will swing three to four feet in each direction or a total swing of seven or eight feet, and while Figure 4 illustrates a hull 35 having 4 the speed of travel is fairly slow, the container can deliver a very damaging blow.

In order to eliminate the evil consequences of this swing, this invention provides two things. Referring to Figure 5, and also to hold 40 of Figure l, applicants use just one deck of supporting beams and these beams run transversely to the ship. The roll of a ship is ordinarily a composite movement resulting from a sideward roll and a lengthwise pitch, but the greatest deviation from the vertical is ordinarily a transverse deviation. It follows that in order to get the containers between the beam deck when there is a roll on the ship, there is much less likelihood of physical encounter between the container and the beams when the beams run transversely of the vessel than when they run longitudinally thereof. This use of a single beam deck is expected to be standard.

Applicants secondly provide a bridge mounted travel crane which has a beam which moves vertically only at right angles to the tank top 36 or to the plane of the weather deck. The beam is limited to vertical movement by guides mounted on the travel crane. At the bottom of the beam are holding means which tightly hold the container. When the ship rolls, the relationship of the beam to the ship hold does not change and this is true if a container happens to be on the end of it. Referring to Figure 4, illustrating a roll of 15 degrees, the container 41 would occupy the dotted line position 42 if unrestrained, but because it is rigidly held to the beam 43, it occupies the position shown and can be moved between the beams 44 and 45 without damaging either. It will be appreciated that tremendous structural strength would be required to hold the beam 44 at the angle indicated in Figure 4-a structural strength which would not be practical in a bridge mounted travel crane positioned on a ship. However, it is not intended that transfer of cargo take place when the vessel is rolling some 20 degrees. It is contemplated that this kind of transfer will take place in a comparatively quiet sea.

A bridge mounted travel crane capable of attaining the objectives described above is illustrated in Figures 6 through 9. Referring to Figures 6 and '7, 45 and 46 identify vertical support members for the bridge mounted travel crane. The lower portion of each of these members 45 and 46 carries wheels such as 48 which ride on rails 49 mounted on an I beam 50 which is supported on the ship stringer 50a. On the under side of the upper cross member of the I beam 50 are rails such as 52 which are engaged by wheels such as 53 mounted on the vertical members 45 and 46. This wheel assembly holds the vertical members to the ship hull and counteracts displacement forces arising from ship rolling or functioning of the bridge mounted travel crane. The vertical support members 45 and 46 are connected at their upper ends by cross beams 58 and 59 to similar vertical members on the other side of the shipthese latter not being shown. Referring to Figure 7, the parallel relationship transversely of the ship of the beams 58 and 59, and of the vertical supports 45 and 46, is maintained by heavy steel beams 5'! connecting the bottoms of the vertical members 45 and 46 and by a tying arrangement of rollers operating through the travel crane itself, as will be later described.

. The upper part of the upright member 45 has an inwardly directed channel construction formed by cross, members 58;, 5.0 and: GI and extending the entire width of the bridge. These channels bear the general numbers 54' and 55. In these. channels. ride two upright girder members 62 and 63 joined at their outer ends by cross. members 64 and 65 (see Figure 8). These members together constitute an auxiliary or telescoping bridge. This telescoping bridge rests. on a series of rollers 64a and continued alignment in the two channels 54 and 55. isassured by auxiliary rollers 65a and 6.6 All three sets of rollers 64a, 65a and 66 aremountedin the channel 54.

Endwise movement of the telescoping bridge in the principal bridge is obtained by means of a rack 61 extendingalong the top of the telescoping bridge and engageable by a pair of pinions 68 and 69mou-nted on shafts III and l l supported in suitable blocks on the main bridge. Sprockets I2 and I3 mounted on the shafts I and H are driven by chains M and 14a which in turn aredrivenby central sprockets I5 and 15a. The sprockets I5 and Ida are mounted on a shaft I6 which carries a pinion 11 that engages a pinion 18 on the shaft of an electric motor I9. Movement of the telescoping brid is restricted so that the cross member 65 doesnot, move past the point 8| and the cross member 64 does not move past the point 83.

Mounted lengthwise along the inside outer length of the telescoping bridge are rails 84 and 85 and inverted rails 8F and Bl. Mounted on the upright portion 6I- are rails 88 and 89 and inverted rails 90 and SI. Disposed between the two bridge members isa travel crane car 92, the

exact construction of which neednot be described. Sufiice it to say that it has two wheels engaging each of the heretofore enumerated rails, namely 84, 85, 86, 81, 88, 89,- 90- and 9I From the constructiondescribed, it is evident that stresses tending to rock the travel crane 92 with respect to the telescoping bridge will be offset by the action of the eight whee-ls riding in the four rails 84, 85, 86 and 8-1, and that consequently such stresses Will be transmitted without substantial alteration of direction to the telescoping bridge while the car remains free to move longitudinally of the telescopingbridge. It is further evident that such stresses will be transmitted by the rollers such as 65 and E6 to the principal bridge itself. Where the telescoping bridge is extended beyond the sides of the principal bridge, as illustrated in Figure 8, and the travel crane 92 is working from a point adjacent to 83 and thence out to the end of the telescoping bridge, the travel car will rest solely on rails 88 and 89, see Figure 7. As rails 88 and 89 and their companion rails 90 and 9| are mounted directly on the travel crane, misaligning stresses transmitted to the travel crane will be transmitted directly to the main bridge without passing through the telescoping bridge. Ship rolling will not derail the bridge from the rails mounted on the ship stringers, nor derail the travel crane 92 from the rails in the telescoping bridge, nor upset the free movement of the telescoping bridge on the rollers 64, 65 and I56 on the principal bridge. The application of such strains to the travel crane 92 will result in the strains being adsorbed not only by the entire bridge structure, but by the ship construction at the ship sheer.

Disposed vertically centrally of the travel crane 92 is a beam IIiI having at its lower end a through slot I02 in which is mounted a pulley I03 disposed on a shaft I04. Extending along the opposite walls. of the beam IIII: through. which the slot I02 passes are grooves I05: and I06; which will receive a cable I01 having one end fixedly fastened at I08. (see Figure 6') and after passing over the pulley I93, carried to. a drum I09. The beam is guidably held in the travel crane 92 for vertical. movement only, either by rollers. IBM or slides.

At the bottom of the beam are located two sets of four hooks, each set operated by power meanscontrolled from the cab of the travel crane 92 and each set capable of liftably engaging the eyelets of a container whether the container be parallel with the length of'the bridge travel crane or at right angles thereto. Referring toFigure 9, to the bottom of thebeam II) t is attached a heavy lifting plate IIO. On each of the four faces of the beam isplaced an air operated piston II I, H2, II-3', and Air is supplied to the pistons through an airline such as I I5, having an electrically controlled valve H6 responsive to a switch not shown positioned in the travel crane cab 92* connected by the circuit II to the electrically controlled valve H6. The principal air supply line is indicated by numeral H8 and (referring to Figure 7) is supplied by a pair of storage tanks H9 and I20 in which pressure is maintained by a compressor I2I driven by an electric motor I22 mounted on a flat plate I2 3 on top of the vertical beam I0 I.

Referring again to Figure 9, a pistonrod I2 1 depends from the piston II I: and to the lower end I25 of the piston III is fastened on opposite sides pivotally a pair of oppositely extending arms I26 and I21. Similar arms, as I28 (see Figure '7 are similarly controlled by the piston II4= on the opposite side of the beam IDI. These arms I26 and I2! rest in channel I29 in the lifting plate. At their outer ends are, referring to arm I'Z'I, cam surfaces I30: and I3I which with a stop I32 form a notch I 33. in the upper surface of the arm. In use, the two: arms such as I26 and I2I extending transversely of any container that is to. be picked up will be in the position indicated by the dotted line I34. In order to couple to a container such as I35,- the crane operator will function both the piston III and H4 which. will cause the associated lifting arms suchas I26- and I2! to move into the solid lineposition shown in Figure 9. Thereupon theoperator raises thebeam IIlI, and the channels I28 and I29 of the lifting plate IIU engage the arms I26 and I2! and. raise the container I35.

Referring to Figure 7, the numerals I36 and I31 identify two flaps hingedly mounted at I38 and. I39 to the upper edges of the bridge mounted travel crane, not shown in Figure 6. These flaps extend the entire width of the bridge mounted travel crane and when fully distended as indicated by dotted line I40, cover in conjunction with the travel crane itself, an area extending lengthwise of the boat by almost two holds. These flaps may be made of translucent material and. are raised by any suitable means such as cables MI and I42. In unloading containers from the vessel to a wharf or some other vessel, container movements will be vertical and horizontally transverse to the length of the ship. That is to say, there will only be movement of the travel crane lengthwise of the ship when unloading of containers in a given transverse line has been completed. Under such circumstances, applicants housed, bridge mounted, travel crane will enable all operations to be conducted out of weather. In the case of moving containers from hold to hold, the large flaps when extended will largely protect two open holds, but if longitudinal movement of the crane must exceed longitudinal movement adjacent two holds, the flaps I36 and 131 will not afford protection.

The crane shown is intended for use in a container ship of the type illustrated in copending application, Serial No. 586,522, particularly Figures 3 and 4 where the containers do not have to be turned 90 in order to get them into their position in the hold. In such holds, the containers have their length positioned transversely of the vessel when they are resting on the hold bottom and they are passed vertically between the transverse beams of the beam deck. Containers positioned on the beam deck have their length running lengthwise of the vessel and they are lifted to and from position by the other set of arms on the bottom of the lifting beam I! of applicants crane. Where two beam decks are employed with the beams of one deck running parallel to the beams of any lower deck or the holding means mounted on the hold bottom of the vessel, it will be necessary to turn a container 90 in order to get it into position. The crane illustrated in this application will not accomplish this end, for the beam I01 can move vertically only.

The numeral I45 identifies the space occupied by a container I46 which was positioned in the hold or is to be positioned in the hold with its length parallel with the length of the vessel. The space in between the vertical support members 45 and 46 is such as to permit such a container to be moved outwardly between them, see Figure 7.

Having thus described our invention, what we claim as new and wish to secure by United States Letters Patent is:

A ship comprising a hull, a weather deck, hatches disposed between the port and starboard ship sheers, a rail running along each ship sheer, and a travel crane movably mounted on said rail and held thereto against displacement b the rolling of the ship, said travel crane comprising a pair of base members, one over each rail, a pair of inverted U-shaped members having their lower ends respectively mounted on the base members so that the U-shaped members are erect, spaced from each other, and span the distance 8 between the two rails, a pair offacing, open--' ended channels, one in each inverted U-shaped member, an auxiliary bridge comprising in plan view a rectangular frame of a width sufficient to nest in said channels and of a length approximating the length of the U-shaped members, means for, sliding the auxiliary bridge laterally between the two U-shaped members, a depending wall on each of the long sides of the auxiliary bridge, a transverse beam mounted on the inside of each of the U-shaped members and extending above the bottom of the depending wall of the auxiliary bridge so that the depending wall is between the beam and the main body of the inverted U-shaped member, a rail on the inside of each of the depending walls of the auxiliary bridge, a rail on each of the beams, and a travel crane having means for supporting it on both the rails of the auxiliary bridge and the rails of the beam. LEATI-IEM D. SMITH.

RICHARD A. STEARN.

WILFRED S. STONE.

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